Image pickup devices are usually used to take photographs or holding video conferences. With increasing development of digital techniques, text documents are gradually created as electronic files. Generally, text documents are scanned by scanning apparatuses and then saved as electronic files such as PDF (Portable Document Format) files. For most companies, the scanning apparatuses are essential apparatuses. For some companies, the scanning apparatuses are not necessarily purchased. In other words, the applications of the scanning apparatuses to create electronic files are limited.
Recently, a method has been proposed for creating electronic files of simple documents (e.g. single-sided papers or business cards) without the need of using the scanning apparatus. In this method, an image pickup device is served as a peripheral device of the computer to capture the image of the document. The captured image of the document is saved as an electronic file. This electronic file is an image file such as a JPEG (Joint Photographic Experts Group) file. Most users prefer using scanning apparatuses to scan the text documents as PDF files because the texts and signs contained in the PDF files are readable by the computer and may be converted as editable text files.
As known, optical character recognition (OCR) is a process of capturing an image of a document and then extracting the texts from the image. Recently, it is possible to analyze images that are captured from the image pickup device by the OCR technique and saved as JPEG files. As a consequence, individual texts or signs contained in the JPEG files are recognized and converted as editable text files. Since the associated OCR techniques are well established, the image pickup device is gradually adopted to obtain electronic files of the documents.
When an image pickup device is used to capture the image of a document, some difficulties possibly occur. For example, it is critical to hold the document steady. For capturing the image of an article contained in the document by the image pickup device of the notebook computer, if this document is held by the user's hand, the document is readily rocked due to the long holding time. Under this circumstance, the obtained document image is usually blurred. For preventing from rocking of the document and thus obtaining a sharp document image, a static document stand is used for holding the document steady. The use of the document stand, however, incurs another problem. For example, in a case that the document stand is used in other places, the user should carry the document stand, which is very troublesome to the user.
Recently, an image pickup system without any document stand has been disclosed in for example Taiwanese Patent Publication No. 200825600, which is entitled “System and method for assisting fixed-focus shooting device to focus”. In this image pickup system, the document to be captured is placed on a platform, and an image pickup device is disposed on a moving device for capturing the image of the document. As the image pickup device is moved to an optimal shooting position by the moving device, it is a suitable time to capture the image of the document by the image pickup device. The image pickup system also uses a program to analyze the image acquired by the image pickup device, thereby judging whether the image pickup device is at the optimal shooting position. The platform has a specified mark. According to the image change of the specified mark correlating with distances, the program may realize the distance between the platform and the image pickup device. According to settings of the program, a notifying signal is generated when the distance between the platform and the image pickup device is close to the optimal shooting distance. The notifying signal may notify the user that it is a suitable time to capture the image of the document. In other words, the conventional image pickup system only provides a relatively large shooting zone of the image pickup device, and the image pickup device is not actually located at the optimal shooting position. In this circumstance, the imaging performance is deteriorated. Moreover, for assuring whether the image pickup device is located at the optimal shooting position, the image needs to be continuously analyzed during the shooting process. That is, the conventional image pickup system wastes much computer resource to judge whether the image pickup device is located at the optimal shooting position.